assume cs: codesg ds: data

data segment 
    db 'Welcome to masm!'
    db '................'
data ends

codesg segment
start: mov ax,data
       mov ds,ax

       mov si,0
       mov di,16
       mov cx,8

s:     mov ax,[si]
       mov [di],ax
       add si,2
       add di,2

       loop s

    mov ax,4c00h
    int 21h

codesg ends

end start
       